Re: Subtracting 128th notes

[Knute Snortum]

--
Knute Snortum


On Thu, Mar 31, 2022 at 8:23 AM Stuart Simon <stuart.sa@gmail.com> wrote:
>
> LilyPond Users:
> I'm running into a scenario where it would be useful to subtract three 128th 
> notes from a longer note's duration while having the longer note still appear 
> as a single note in the printed score. This is useful when I have a printed 
> score with three grace notes that I want to be played on the beat rather than 
> before it, but the grace notes are understood differently from both the 
> acciaccatura and the stereotypical "eighth-note with grace upper neighbor 
> plus two sixteenths equals four sixteenths" type of appoggiatura commonly 
> found in Classical-era music. Please do not stop reading this when I tell you 
> that this may be a feature request, for it may also be a simple exercise in 
> finding the right duration scale factor.
>
> When the longer note is a whole note, the case is very simple. The duration 
> is 1 * (1 - 3/128) = 1 * 125/128.
>
> When the longer note is a half note, the case is more complicated. In my 
> mind, the duration  should be 2 * 61/64, but I don't know if that is correct.
>
> Similarly, when the longer note is a quarter note, the duration should be 4 * 
> 29/32.
>
> One more example, this one using a dotted duration. The duration of a dotted 
> quarter note is 3/8 of a measure, so the duration should be 4. * 
> ((1/128)/(3/8)) = 4. * 1/48.
>
> I still don't know if I am correct or not,  but if I am, then it would ease 
> my mind a bit.

The best way to test your theory is to create a tiny example:

%%%
\version "2.22.2"

\relative c' {
  c128 d e f1*125/128 |
  c128 d e f2*61/64 f2 |
  c128 d e f4*29/32 f2. |
}
%%%

That compiles without a barline warning, so it's correct.  I didn't
try your 4. duration example because I didn't understand it enough to
write a good test -- but you can!